Alternatively, if you want to enjoy 78 hours run time per charge, select its trippy Femto mode, which gradually fades between high and low beam approximately once every second. Despite its low drain on the battery, Lezyne's Femto mode is bright enough to ensure you're legal and can be seen after dark. What's more, if your batteries are running low, switch to Femto and the output is still bright enough to illuminate the path immediately ahead of your front wheel when riding, say, a cyclepath after dark.